英文:
Unable to convert AnyPublisher to Another AnyPublisher
问题
以下是您提供的代码的中文翻译部分：
我正在尝试从AnyPublisher中获取一些模型，并使用该模型从另一个发布者获取数组。以下是我的代码：
public func getAllMyAppointments() -> AnyPublisher<[TelehealthMyAppointmentsListEntity]?, Error> {
telehealthMyAppointmentsAPIAccessTokenUseCase.getAccessToken().map { tokenDetails in
provider.getAllMyAppointments(with: tokenDetails)
}
.eraseToAnyPublisher()
}
但我得到了以下错误：
> 无法将类型为'AnyPublisher<[TelehealthMyAppointmentsListEntity]?, any Error>'的值转换为闭包结果类型'[TelehealthMyAppointmentsListEntity]?'
以下是我的方法签名：
func getAccessToken() -> (AnyPublisher<MyAppointmentsAPIAccessTokenDetails, Error>)
func getAllMyAppointments(with accessInformation: MyAppointmentsAPIAccessTokenDetails) -> AnyPublisher<[TelehealthMyAppointmentsListEntity]?, Error>
请注意，我只翻译了您提供的代码部分，没有包括其他内容。
英文:
I am trying to fetch some model from an AnyPublisher and using model get an array from another publisher. Following is my code:
public func getAllMyAppointments() -> AnyPublisher<[TelehealthMyAppointmentsListEntity]?, Error> {
telehealthMyAppointmentsAPIAccessTokenUseCase.getAccessToken().map { tokenDetails in
provider.getAllMyAppointments(with: tokenDetails)
}
.eraseToAnyPublisher()
}
But I am getting following error:
> Cannot convert value of type 'AnyPublisher<[TelehealthMyAppointmentsListEntity]?, any Error>' to closure result type '[TelehealthMyAppointmentsListEntity]?'
Following is signature for my methods:
func getAccessToken() -> (AnyPublisher<MyAppointmentsAPIAccessTokenDetails, Error>)
func getAllMyAppointments(with accessInformation: MyAppointmentsAPIAccessTokenDetails) -> AnyPublisher<[TelehealthMyAppointmentsListEntity]?, Error>
答案1
得分: 2
你在这里使用了 map，但实际上应该使用 flatMap。
对于一个类型为 AnyPublisher<T, Error> 的对象，使用 map 的目的是将其从 T 转换为 U，得到一个 AnyPublisher<U, Error>。
但是你想要的是使用一个 (T) -> AnyPublisher<U, Error> 来执行相同的操作，这正是 flatMap 的用途：
public func getAllMyAppointments() -> AnyPublisher<[TelehealthMyAppointmentsListEntity]?, Error> {
telehealthMyAppointmentsAPIAccessTokenUseCase.getAccessToken().flatMap { tokenDetails in
provider.getAllMyAppointments(with: tokenDetails)
}
.eraseToAnyPublisher()
}
英文:
You've used map when you mean flatMap.
For an AnyPublisher<T>, the point of map is to use a (T) -> U to convert AnyPublisher<T> to AnyPublisher<U>.
But what you want is to use a (T) -> AnyPublisher<U> to do the same thing. That is precisely flatMap:
public func getAllMyAppointments() -> AnyPublisher<[TelehealthMyAppointmentsListEntity]?, Error> {
telehealthMyAppointmentsAPIAccessTokenUseCase.getAccessToken().flatMap { tokenDetails in
provider.getAllMyAppointments(with: tokenDetails)
}
.eraseToAnyPublisher()
}
</details>
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